NO在负载型金属氧化物催化剂上的氧化反应机理

Reaction Mechanism of NO Catalytic Oxidation over Supported Metal Oxides

研究了γ- Al2 O3负载的金属氧化物催化剂对 NO催化氧化性能。实验发现 ,30 0°C下催化剂活性顺序为 Mn>Cr>Co>Cu>Fe>Ni>Zn,P-型金属氧化物对 NO的氧化活性较强。对 Mn O2这种具有代表性的 P-型金属氧化物催化剂 ,提出了其 NO催化氧化的反应机理和动力学模型。

The catalytic oxidation of NO is investigated over metal oxide catalysts supported on γ alumina. The experiment results show that P type metal oxide catalysts display relatively high catalytic acti vity and the sequence of activities for NO oxidation is as follows: Mn>Cr>Co>Cu>Fe>Ni>Zn By using a micro reactor, the reaction mechanism of catalytic oxidation over a typical P type metal oxide catalyst MnO 2 can be expressed as: 12O 2+v k 6 k′ 6O(ads) O(ads)+NO(g) k 7 k′ 7NO 2(ads) NO 2(ads) k 8 k ′ 8NO 2+v Surface reaction is the critical step and the reaction kinetic equation can be expressed as: r NO = k 7 b O 2 p 1/2 O 2 p NO 1+ b O 2 p 1/2 O 2 1- p NO 2 K P p NO p 1/2 O 2 By means of non linear regression, the reaction activation energy and reverse activation energy of MnO 2/ γ Al 2O 3 is specified as 25.2, 81.4kJ/mol respectively.